Thermostatic switch



June 5, 1934. w. PAULlNG 1,961,778

THERMOSTATIC SWITCH Filed April 8, 1932 2 Sheets-Sheet l I-vz-on JOHNW-PAULJNG June 5, 1934. w PAULING 1,961,778

THERMOSTATIC SWITCH Filed April 8, 1932 2 Sheets-Sheet 2 25 lo 29 3aINVENTOR JOHN W-PAULING TT'ORNEYS.

Patented June 5, 1934 UNITED STATES THERMOSTATIC SWITCH John W. Pauling,Minneapolis, Minn assignor to Minneapolis-Honeywell Regulator Company,Minneapolis, Minn., a corporation of Delaware Application April 8, 1932,Serial No. 804,015

19 Claims.

This'invention relates generally to improvements in switching mechanism,and contemplates a mechanism which can be used for various purposes withor without thermostatic control. Specific embodiments of the inventionare also claimed both in combination and subcombination, and one ofthese embodiments relates to the overlapping controlvof contacts orswitches during temperature rise and a nonoverlapping control duringtemperature fall. A claimed combination includes as an element, athermostatically controlled means, exemplifled in the application ofDaniel G. Taylor for Thermostatic switch, Serial Number 539,224, filedMay 22, 1931.

The present invention also provides means by which a hold-over contactpressure is maintained during opening of a contact or switch, so thatthe contact will not be prematurely opened.

Features include the along with the broader ideas of means inherent inthe disclosure.

Objects, features and advantages of the invention will be set forth inthe description of the drawings forming a part of this application andin said drawings Figure l is a face view of one embodiment of theinvention with the mechanism at one control position, as when thethermostat is at "cold position;

Figure 2 is a vertical longitudinal section through a stack thermostator combustion responsive device, taken on line 2-2 of Figure 1; andFigure 3 is a view similar to Figure 1 showing the mechanism at theopposite control position,

or as during heating of the thermostat.

Referring first to Figure 2 of the drawings:

Numeral 1 indicates a suitable casing for housing the switch and theprincipal parts of the control mechanism. Numeral 2 indicates a tubularelement suitably attached at the back of the casing. This element isadapted to pass through the wall of the stack, and is suitably securedto the stack by a bracket 3. Passing through the tubular member is ashaft 4 suitably journaled in the outer end of the tube and alsojournaled at its opposite end in a bearing 5 arranged within the casingi; A spiral ribbon or thermostatic bimetallic element 6, secured atopposite ends as at 7-8, respectively to the tube 2 and the shaft 4,constitutes the usual thermostatic means for. rotating the shaft detailsof construction (on. zoo-1st) to a sleeve 9, rotatable upon the tubularbearing 5 is a slip friction assembly generally indicated at 10 and asuitable spring 11 applies pressure to theend disk 12 of the frictiondevice. Between two of the friction disks and rotatable on the sleeve 9is a bead-supporting disk 14 having a bead 15 of insulating material.This bead is adapted to engage one side of and move a resilient switcharm 16 suitably secured to the bracket 17 mounted on insulating block18. The arm is connected to the bracket by resilient blade 19. This arm16 is biased to move to a mid-position with reference to two contacts,one of which is carried by resilient arm 20, and the other of which iscarried by stationary extension 21. The arm and extension will bereferred to respectively as contacts 20-21. When the shaft 4 is rotatedin clockwise direction, in this instance on temperature fall, the arm 16is moved by bead 15 to the left or, in this instance, in direction ofthe cold contact 21.

Mounted also between the friction disks is a bead-supporting disk havinga bead 26 of insulating material adapted to engage the opposite side ofthe control arm 16 when the shaft 4 is rotated in counter-clockwisedirection due, in this instance to rise in temperature. When movedsuillciently by the bead 26, the control element 16 engages theresilient arm 20.

Sufilcient frictional resistance is provided for the bead mounts .toobtain forced motions of the control element 16 to either controlposition, without slippage. After the proper amount of movement, thefrictional force is overcome and the rotation of 'the'sleeve 9 maycontinue independently of the mounts 14 and 25. In order to obtainrotation of the sleeve 9 as the result of rotation of the shaft 4, disk30 is secured to the shaft 4 to move therewith. The disk is peripherallyformed to provide a shoulder 31, see Figures 1 and 3. Rotatable also onshafts is a slotted plate 32 having a radial shoulder 33. A set screw34. passing through the slot and threaded into the disk 30 providesmeans for securing the plate (after rotative adjustment) for rotationwith the disk. The disk 29, fixed to sleeve 9, is provided with anextension35 which lies in the path of the shoulders 31, 33, and it willbe seen that by properly adjusting the slotted plate 32, either a lostmotion, or a non-lost motion, connection can be obtained. When rod 4'rotates, the sleeve and beads 15 and 26 are correspondingly moved.

The above decsribed mechanism is only claimed herein broadly as means bywhich the element 16 can be thermostatically controlled, and/or as meansadapted to control the element 16 in certain predetermined andadjustable relations to the switch mechanism now to be described.

The mechanism of this invention may be used independently of thethermostat, but the control of the contacts overlappingly duringtemperature rise and nonoverlappingly during temperature fall is avaluable feature of the invention.

Associated with and controlled by the element 16 is a relatively stiil.arm 40 spaced from the arm 16 and secured as by riveting to theextension of a plate 11. This plate is rotatable about a post 42suitably immovably connected to conducting element 39 embedded in theinsulating block 18. The post traverses a cup 43 embedded in theinsulating block 18. Held in this cup, is a friction washer 43 againstwhich the plate 41 engages. Means is provided to press the plate 411against the friction washer. This means comprises a spring 44surrounding the post, and a nut fifi threaded on the post for varyingthe compression of the spring, to adjust the degree of friction. Thusthis plate is posi tively held in any position to which it is moved bythe arm 40, but can. be forcibly moved from. that position. The arm 40has a contact-en gaging element resiliently fulcrumed thereto by meansof a short resilient element or blade 51, so as to be rockable againstthe action of this resilient means after the element engages its contactand on its continued motion toward the contact. The arm 40 has stopmeans 53 engageable by the lower or contact-making arm of the rockingelement ior limiting rocking motion, when moving away from the contact.The lower arm swings between stop 53 and arm 40. The resilientconnection. 51 is attached at that side of the contactor 50 and arm 40which faces away from the contact 21.

The lower arm of the rocking element 50 has the usual button whichengages the contact 21, and the upper arm of: this element lies between.spaced abutments of a lost motion connecting means which is carried bythe arm 16, and by means oi which this first arm controls the second.the present instance, this means comprises two heads of insulatingmaterial 55--56 spaced apart and adapted to alternately engage the upperarm oi the rockable contactmaking element 50:. The resilient rockingarrangement provides means by which sufficient contact pressure can beirnaintainecl during motion in contact-opening direction, to preventpremature opening after head 55 moves away from or releases the rockableelement 40 and before engagement of bead 56 with element 50, that isduring the lost motion period.

It is conceivable that in some instances, the second arm can be directlyoperated by the beads of the lost motion connection, and not through therockable contact-making element. How ever, to obtain sufficient contactpressure during temperature rise, or during opening of the contact, thisresiliently controlled rockable device is valuable.

The bracket 5'? is provided with stops lying at opposite sides of theresilient blade or contact 20 to limit its movement in both directions.The stop for limiting its movement toward the control arm 16 consists ofa relatively stifi arm 60 secured by the same fastening device whichsecures the blade 20 to the bracket. The other stop is a bent-outportion 61 of the bracket 57. The blade 20 is biased to move against thearm 60.

A feature of this invention relates to the arrangement of the arms,contacts, and lost motion means whereby on temperature rise, contact 21will notbe opened until contact 20 is closed, and so that on temperaturefall, contact 21 will not be closed until contact-20 is opened. In otherwords, so that on temperature rise, the contacts are overlappinglycontrolled, and on temperature fall, non-overlappingly controlled.

Operation Let is be assumed that the parts are positioned as shown inFigure 1, corresponding to cold position of the thermostat. In thisposition, bead 26 is against calibration stop 64, arm 16 is against head26, bead 15 is engaging the opposite side of the arm 16, and contact 21is closed, and the resilient means 51 of the rocking element 50 is undertension. 0n rise in temperature, the beads both move together inanti-clockwise direction, releasing control arm 16 which travels withthe beads to its midposition, under its own bias. At the beginning ofthis movement, bead 55 of the lost motion connection moves way fromcontactor 50, but contact 21 remains closed, by action of its frictionmeans and resilient blade 51. As the motion continues, the opposite bead56 moves toward the element 50 from the opposite side. As' shown, theparts are so related that contact 20 is closed before the abutment bead56 acts to open contact 21. After contact 20 is closed, it continues tomove toward the position shown in Figure during which movement 56engages and moves 50 to open. contact 21. During the motion in thedirection. shown and after the switches have assumed the position shownin Figure 3, the beads 15, 26 will have assumed the position shown, andthe head 15 will have engaged the stop 65. 1

On fall in temperature, the first action is by bead 26 to allow controlelement 16 to move to open. the contact 20. During this movement, head56 oi the lost motion connection moves away from contactor 50, butcontact 21 remains open until 50 is finally engaged and moved by bead 55toward, and finally against, contact 21.

After 50 engages the contact 21, bead 55 still. acting on 50 continuesto move it in the same direction against the action of the spring blade51 and the contactor is thus conditioned to exert the proper pressure tomaintain a closed contact, when. the contactor 50 is released, due tomovement of the arm 16 toward. the right.

I claim as my invention:

1. A first arm, a contact controlled thereby, thermostatically operablemeans for controlling the arm, including a lost motion connection, asecond arm and a contact controlled thereby, and means by which thefirst arm controls the second to overlappingly control the contacts ontemperature rise, and non-overlappingly control them on temperaturefall.

2. A first arm, a contact controlled thereby, thermostatically operablemeans for controlling the arm, including an adjustable lost motionconnection, a second arm and a contact controlled thereby, and means bywhich the first arm controls the second to overlappingly control thecontacts on temperature rise and non-overlappingly control them ontemperature fall, said means including a lost motion connection betweenthe arms.

3. A device of the class described comprising a first arm and contactcontrolled thereby, a sec-' ond arm and contact controlled thereby, alost motion connection by means of which the first arm controls thesecond, thermostatic means for operating the first arm, including a lostmotion connection, said means and the arms, contacts, and arm-operatingmeans being so related that on temperature rise one contact is closedbefore the other is opened, and on temperature fall that contact firstto close is opened before the other is closed.

4. A first resilient arm biased to assume a midposition with relation totwo contacts and adapted to directly control one contact, a second armcontrolling the other contact, and means by which the first armcontrolsthe second, including a lost motion connection which acts alternately inboth directions.

5. A first arm, a contact controlled by said arm during motion in onedirection, a second arm and contact controlled thereby, means by whichthe first arm controls the second including abutments so spaced that thesecond arm is caused.

reverse movement of the first arm, the second arm acts to close itscontact only after the first has opened its contact.

6. A first arm, a contact controlled by said arm during motion in onedirection, a second arm and contact controlled thereby to be closed whensaid first arm moves in an opposite direction, means by which the secondarm is yieldably but positively held in any position to which it ismoved, means by which the first arm controls the second during motion ineither direction including spaced abutments, said second arm having acontact-engaging element engageable by the abutments, means by which thecontactengaging element is resiliently fulcrumed to the arm to berockable against the action of the resilient means after the elementengages the contact and on continued motion of the arm in contact-makingdirection.

7. A first arm biased to assume a mid-position, a contact controlled bysaid arm during motion in one direction from its mid-position, a secondarm and contact controlled thereby, means by which the second arm isyieldably but positively held in any position to which it is moved,means by which the first arm controls the second during motion in eitherdirection, in-- cluding stops so spaced that the second arm is caused toopen its contact only after the first arm has caused closure of itscontact, and so that on reverse movement of the first arm, the secondarm acts to close its contact only after the first has opened itscont-act, said second arm having a contact-engaging element and means bywhich it is resiliently fulcrumed to the arm to be rockable against theaction of the resilient means after the element engages the contact andon continued motion of the arm in contact-main ing direction, andthermostatically controlled means adapted to control the first arm incertain predetermined and adjustable relations to temperature change. I

8. A contact control element, a theremostatically controlled support, apair of abutments on the support independently movable, each adapted tomove the control element in a different direction, means frictionallyresisting indeis moved, and means for adjusting the degree of friction.

9. A switching structure including a control arm, and contact controlledthereby, said arm having a contact-engaging element and means by whichthis element is resiliently fulcrumed to the arm to be rockable againstthe action of the resilient means after engaging its contact and oncontinued motion of the arm in contact-making direction.

10. A switching structure including a control arm, and contactcontrolled thereby, said arm having a contact-engaging element and meansby which this element is resiliently fulcrumed to 'the arm to berockable against the action of the resilient means after engaging itscontact and on continued motion of the arm in contact-making direction,and operating means engageable with the contact-engaging element.

11. A switching structure, including a control arm, and contactcontrolled thereby, said arm having a contact engaging element and meansby which this element is resiliently fulcrumed to the arm, said elementbeing rockable against the action of the resilient means after engagingits contact and on continued motion of the arm. in contact-makingdirection, means for limiting the rocking motion of the contact-ento thearm, said element being rockable against the action of the resilientmeans after engaging its contact and on continued motion of the arm incontact-making direction, operating means engageable with thecontact-engaging element, and means carried by the arm for limitingrocking motion of the contact-engaging element when moving away from thecontact, saidelement and arm being so related that the arm forms a stopfor limiting movement of the element after engaging its contact.

13. A switching mechanism comprising, an actuator movable through arelatively large range, a pair of abutments, continuously acting slipfriction means connecting the actuator and abutments, a control elementalternately engageable by said abutments upon reverse movements of saidactuator circuit controlling mechanism controlling first and secondcircuits, and means by which said control element operates saidmechanism for closing the first circuit and 14. A switching mechanismcomprising, an,

actuator movable through a relatively large range, a pair of abutments,continuously acting slip friction means connecting the actuator andabutments, a control element alternatively engageable by said abutmentsupon reverse movements of said actuator, circuit-controlling mechanismcontrolling first and second circuits, and means by which said controlelement operates said mechanism for closing the first circuit andthereafter opening the second upon movement of the control elementin'one direction, and opening the first circuit prior to closing of thesecond circuit on movement of the control element in the oppositedirection, and means for limiting the movement of the abutments beyondthe control element on continued movement of the actuator.

a 15. A switching mechanism comprising, an actuator movable through arelatively large range, a pair of abutments, continuously acting slipfriction means connecting the actuator and abutments, a control elementalternately en- ,gageable by said abutments upon reverse movements ofsaid actuator, circuit controlling mechanism controlling first andsecond circuits, and means by which said control element operates saidmechanism for closing the first circuit and thereafter opening thesecond upon movement of the control element in one direction, andopening the first circuit prior to closing of the second circuit onmovement of the control element in the opposite direction, and means foradjustably limiting themovement of at least one of the abutments afterthe same leaves the control element on continued movement of theactuator whereby the amount of reverse movement of the actuatornecessary to cause engagement of said abutment with the control elementmay be varied.

16. A device of the class described comprising, in combination, a firstarm movable through a limited range of movement, a switch directlycontrolled thereby and normally in open circuit position, a secondarm, asecond switch directly controlled thereby and normally in closed circuitposition, a lost motion connection between the arms whereby movement ofthe first arm in one direction moves its switch to circuit closedposition and thereafter moves the second arm through the lost motionconnection to move its switch to open circuit position, and reversemovement of the first arm moves its switch to open circuit position andthereafter moves the second am through the lost motion connection toclose its switch, an actuator adapted to move in reverse directions, andslip friction connecting means between the actuator and first armwhereby the actuator may continue moving unrestrictedly after it hasmoved said first arm to either end of its limited range of movement.

17. A devicegof the class described comprising, in combination, a firstarm movable through a limited range of movement, a switch directlycontrolled thereby and normally in open circuit position, a second arm,a second switch directly controlled thereby and normally in closedcircuit position, a lost motion connection between the arms wherebymovement of the first arm in one direction moves its switch to circuitclosed position and thereafter moves the second arm, through the lostmotion connection, to move its switch to open circuit position, andreverse movement of the first arm moves its switch to open circuitposition, and thereafter moves the second arm through the lost motionconnection to close its switch, an actuator movable in reversedirections, a first abutment, slip friction connecting means connectingsaid first abutment and actuator, said abutment being adapted to engagesaid first arm and move the same to one end of its limited range ofmovement upon movement of the actuator in one direction and thereafterallow continued unrestricted movement of the actuator in the samedirection, a second abutment, slip friction connecting means between thesecond abutment and the actuator, said second abutment, upon movement ofthe actuator in the reverse direction, engaging the first arm to movethe same to the other end of its limited range of movement andthereafter permit continued unrestricted movement of the actuator in thesame direction and means for limiting the movement of said abutmentswhen moved away from said first arm by said actuator.

18. A switching mechanism comprising, an actuator movable through arelatively large range of movement, a pair of abutments, continuouslyacting slip friction means connecting the actuator and the abutments, acontrol element movable through a limited range of movement andalternatively engaged by said abutments upon reverse movements of saidactuator, a pair of switches normally resting in opposite circuitcontrolling positions, and means associ ated with the control elementand switches for moving one of said switches to a new circuitcontrolling position prior to moving the other of said switches to a newcircuit controlling position upon movement of said control element ineither direction, said slip friction connecting means permittingcontinued unrestricted movement of said actuator after said abutmentshave moved the control element to either end of its limited range ofmovement.

19. A switching mechanism comprising, an actuator movable through arelatively large range of movement, a pair of abutments, concuit closedposition and thereafter moving said second switch to circuit openposition upon movement .of said control element in one direction and formoving the first switch back to open circuit position prior to movingthe sec-- ond switch back to circuit closed position upon movement ofthe control element in the other direction, and means for limiting thetravel of each of said abutments in a direction away from said controlelement, said slip friction connecting means permitting continuedunrestricted movement of the actuator when further movement of saidabutments is prevented.

JOHN W. PAULING.

